Image projection apparatus

ABSTRACT

An image projection apparatus includes a light source, light from which is used to project an image, and a holding member configured to hold the light source. The holding member includes a handle portion, and the handle portion includes a first flow path for flowing air.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to and incorporates by reference the entire contents of Japanese Patent Application No. 2011-242927 filed in Japan on Nov. 4, 2011.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image projection apparatus.

2. Description of the Related Art

Conventionally, there is known an image projection apparatus provided with an image forming unit to form an image with light emitted from a light source on the basis of image data from a personal computer (PC), video camera or the like, so that the image is projected and displayed on a screen or the like.

As the light source of the image projection apparatus, a halogen lamp, a metal halide lamp, a high pressure mercury lamp and the like may be used. These kinds of lamps become high temperature when emitting light. Therefore, the image projection apparatus is provided with a light source cooling unit for cooling the light source by flowing air to the light source by an air flowing device such as a blower and a fan (e.g. Japanese Patent Application Laid-open No. 2003-5292 and International Publication No. WO02/097529).

The light source reaches its end of lifetime after use over time. Therefore, the image project apparatus has a configuration allowing for the replacement of the light source by the user. Specifically, an outer case of the image projection apparatus has a replacement opening for detaching and attaching the light source unit including the light source from and to a main body of the apparatus. An access cover which is an openable and closable cover to open and close the replacement opening is also provided. When the user replaces the light source, the user remove the access cover from the outer case, grab a handle formed on the light source unit to pull out the light source unit from the replacement opening, and insert a new light source unit from the replacement opening to attach the new light source unit to the main body. Thus, the light source unit is replaced.

In many cases, the light source unit is provided with a handle allowing for the user to grab it by hand or pinch it by fingers for the improved operability in replacing the light source unit. However, the handle of the light source unit becomes also high temperature due to heat conductance or heat radiation from the light source. As a result, when the light unit is to be replaced due to the end of lifetime of the light source during operation of the image projection apparatus, the user cannot grab or pinch the handle. Thereby, the user has to wait to replace the light source unit until the handle is cooled sufficiently. Therefore, the downtime of the apparatus is disadvantageously long.

SUMMARY OF THE INVENTION

It is an object of the present invention to at least partially solve the problems in the conventional technology.

An image projection apparatus includes a light source, light from which is used to project an image, and a holding member configured to hold the light source. The holding member includes a handle portion, and the handle portion includes a first flow path for flowing air.

A light source unit attachable to and detachable from a main body of an image projection apparatus includes a light source, light from which is used to project an image, and a holding member configured to hold the light source. The holding member includes a handle portion, and the handle portion includes a first flow path for flowing air.

The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a perspective view illustrating a projector and a projection plane according to an embodiment;

FIG. 2 is a view illustrating light paths from the projector to the projection plane;

FIG. 3 is a perspective view schematically illustrating an inner structure of the projector;

FIG. 4 is a perspective view schematically illustrating a light source unit;

FIG. 5 is an exploded view perspectively and schematically illustrating the light source unit;

FIG. 6 is a perspective view illustrating optical system components housed in a lighting unit, illustrating with other units;

FIG. 7 is a perspective view illustrating the lighting unit, a projection lens unit, and an image forming unit, viewed from a direction indicated by an arrow A in FIG. 6;

FIG. 8 is a view illustrating light paths in the lighting unit;

FIG. 9 is a perspective view illustrating the image forming unit;

FIG. 10 is a perspective view illustrating a first optical unit with the lighting unit and the image forming unit;

FIG. 11 is a section along A-A line in FIG. 10;

FIG. 12 is a perspective view illustrating a second optical system held in a second optical unit, illustrating with the projection lens unit, the lighting unit, and the image forming unit;

FIG. 13 is a perspective view illustrating the second optical unit with the first optical unit, the lighting unit, and the image forming unit;

FIG. 14 is a perspective view illustrating light paths from the first optical system to the projection plane;

FIG. 15 is a schematic view illustrating an arrangement of units in the apparatus;

FIG. 16 is a view illustrating a usage example of the projector according to the embodiment;

FIG. 17 is a view illustrating a usage example of a conventional projector;

FIG. 18 is a view illustrating a usage example of a projector in which a light source and a lighting unit are aligned in a direction orthogonal to a projection plane;

FIG. 19 is a view illustrating another usage example of the projector according to the embodiment;

FIG. 20 is a perspective view illustrating the projector from an installation side thereof;

FIG. 21 is a perspective view illustrating a state that an access cover is removed from the apparatus;

FIG. 22 is a view illustrating airflows in the projector;

FIG. 23 is a view illustrating the configuration illustrated in FIG. 22 more specifically;

FIG. 24 is a section along A-A line in FIG. 23;

FIG. 25 is a section along B-B line in FIG. 23;

FIG. 26 is a perspective view illustrating a cooling unit for cooling a DMD and the like, illustrating with the lighting unit and the light source unit;

FIG. 27 is a longitudinal section of FIG. 26;

FIG. 28 is a perspective view illustrating a horizontal duct and the light source unit with a base component;

FIG. 29 is a view illustrating airflows from the horizontal duct to a light source bracket, viewed from a lower side of the base component; and

FIG. 30 is a perspective view illustrating airflows from the horizontal duct to the light source bracket, viewed from an upper side of the base component.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of a projector as an image projection apparatus according to the present invention will be described with reference to the accompanying drawings. FIG. 1 perspectively illustrates a projector 1 and a projection plane 101 such as a screen according to an embodiment. Incidentally, in the following explanation, a normal line direction of the projection plane 101 is referred to as X direction, a short axis direction (vertical direction) of the projection plane 101 is referred to as Y direction, and a long axis direction (horizontal direction) of the projection plane 101 is referred to as Z direction.

As illustrated in FIG. 1, a transmissive glass 51 from which a projection image P is emitted is disposed at a top surface of the projector 1. The projection image P emitted from the transmissive glass 51 is projected on the projection plane 101 such as a screen.

Furthermore, at the top surface of the projector 1, an operating part 83 by which a user operates the projector 1 is disposed. At a side surface of the projector, a focus lever 33 for a focus adjustment is disposed.

FIG. 2 illustrates light paths from the projector 1 to the projection plane 101.

The projector 1 is provided with (i) a light source unit including a light source and (ii) an image forming part A to form an image by using a light from the light source. The image forming part A includes (i) an image forming unit 10 provided with a DMD (Digital Mirror Device) 12 as an image forming element and (ii) a lighting unit 20 for reflecting the light from the light source to the DMD 12 so that an optical image is generated. The projector 1 is also provided with a projection optical system B to project the image on the projection plane 101. The projection optical system B has at least one transmissive refracting optical system and includes (i) a first optical unit 30 provided with a first optical system 70 which is a coaxial optical system having a positive power and (ii) a second optical unit 40 provided with a reflecting mirror 41 and a concave mirror 42 having a positive power.

The DMD 12 is irradiated with the light from the light source by the lighting unit 20. The light irradiated by the lighting unit 20 is modulated to form the image. The optical image formed by the DMD 12 is projected on the projection plane through the first optical system 70 in the first optical unit 30, and the reflecting mirror 41 and the concave mirror 42 in the second optical unit 40.

FIG. 3 schematically and perspectively illustrates an internal structure of the projector 1.

As illustrated in FIG. 3, the image forming unit 10, the lighting unit 20, the first optical unit 30, the second optical unit 40 are aligned in Y direction in the figure among directions parallel to the projection plane and an image plane of the projection image. The light source unit 60 is disposed at a right side in the figure of the lighting unit 20.

Incidentally, in FIG. 3, reference numerals 32 a 1 and 32 a 2 refer to legs of a lens holder 32 of the first optical unit 30, and reference numeral 262 refers to a screw clamp portion for screwing (fixing by screw) the image forming unit 10 to the lighting unit 20.

Next, each unit structure will be described.

First, the light source unit 60 will be described.

FIG. 4 schematically and perspectively illustrates the light source unit 60. FIG. 5 is a schematic exploded view of the light source unit 60.

The light source unit 60 includes a light source bracket 62 which is a holding member for holding the light source 61. A light source 61 such as a halogen lamp, a metal halide lamp and a high pressure mercury lamp is mounted on the light source bracket 62. The light source bracket 62 is provided with a connector portion 62 a for connecting with a power source side connector connected to a power source unit 80 (see FIG. 15).

A holder 64, which holds a reflector and the like, is screwed to the upper side of the light source bracket 62 on a light emitting side of the light source 61. The holder 64 has an emitting window 63 at an opposite side to a side where the light source 61 is disposed. The light emitted from the light source 61 is collected to the emitting window 63 by the reflector 67, which is held by the holder 64, and emitted from the emitting window 63.

Light source positioning portions 64 a 1 to 64 a 3 are disposed at a top side and at X direction both ends of a bottom side of the holder 64, for positioning the light source unit 60 relative to a lighting bracket 26 (see FIG. 7) of the lighting unit 20. The light source positioning portion 64 a 3 disposed at the top side of the holder 64 is a protrusion or has a protrusion-like structure. The light source positioning portions 64 a 1 and 64 a 2 disposed at both ends of the bottom side of the holder 64 are holes or have hole-like structures.

At a side surface of the holder 64, a light source air inlet 64 b is disposed for allowing an incoming flow of the air to cool down the light source 61. At a top surface of the holder 64, a light source air outlet 64 c is disposed for allowing an outgoing flow of the air heated by the light source 61.

The light source bracket 62 is provided with an airflow path 65 for allowing an incoming flow of the air taken from an air intake blower (see FIG. 22 and the like) as described later. A sectional shape of the airflow path 65 in which air flows is a rectangle or nearly rectangle. An end of the airflow path 65 is a wall. A thickness of walls of the airflow path 65 is constant or almost constant. Thereby, when viewed from a side which is not used as the airflow path 65, it is observed as a cuboid-like protrusion. As illustrated in FIG. 20, on a surface of the light source bracket 62 opposite to another surface on which the light source 61 is held, nearly rectangular convex portion is formed along the shape of the airflow path 65. This convex portion can be used as a handle portion 68 allowing for the user to pinch the handle portion 68 by fingers to pull out the light source unit 60 for the replacement thereof. Therefore, the outer wall itself of the airflow path 65 is a shape of the handle portion 68. In order to use the airflow path 65 as the handle portion, however, the outer wall itself of the airflow path 65 does not need to be precisely the handle shape, and may have some modification in its shape within an extent that the user can pinch it by fingers. At the air intake side (front side in the figure) of the airflow path 65, openings 65 a are disposed for guiding a part of the airflow flowing into the airflow path 65 to between the light source unit 60 and an access cover 54 (see FIG. 8) which will be described later. The cooling of the light source unit 60 will be described later.

A planar portion 64 d 2 on which the light source positioning protrusion 64 a 3 is formed as illustrated in FIG. 4, and planar portions 64 d 1 provided with the light source positioning holes 64 a 1 and 64 a 2 are abutting members for abutting against the lighting bracket when pressed by a pressing member of the access cover, as described later.

Next, the lighting unit 20 will be described.

FIG. 6 perspectively illustrates optical system components housed in the lighting unit 20, while also illustrating other units.

As illustrated in FIG. 6, the lighting unit 20 includes a color wheel 21, a light tunnel 22, two relay lenses 23, a cylinder mirror 24, and a concave mirror 25, which are held by the lighting bracket 26. The lighting bracket 26 has a housing-like portion 261 in which two relay lenses 23, the cylinder mirror 24, and the concave mirror 25 are housed. Among four lateral sides of the housing-like portion 261, only right lateral side in the figure has a wall. Other three lateral sides are opened. At the opening of the lateral side deep in X direction in the figure, an OFF light board 27 (see FIG. 7) is attached. At the opening of the front lateral side in X direction in the figure, a cover component is attached. Thereby, two relay lenses 23, the cylinder mirror 24, and the concave mirror 25, which are housed in the housing-like portion 261 of the lighting bracket 26, are surrounded by the lighting bracket 26, the OFF light board 27 (see FIG. 7), and the cover component.

At a bottom side of the housing-like portion 261 of the lighting bracket 26, a lighting through hole 26 d is formed for exposing the DMD 12.

The lighting bracket 26 has three legs 29. These legs 29 abut on a base component 53 (see FIG. 20) of the projector 1 to support weights of the first optical unit 30 and the second optical unit 40 which are stacked and fixed on the lighting bracket 26. These legs 29 disposed as such form a space for allowing an incoming flow of ambient air to a heat sink 13 (see FIG. 7) as a cooling unit to cool down the DMD 12 of the image forming unit 10, which will be described later.

Incidentally, in FIG. 6, reference numerals 32 a 3 and 32 a 4 refer to legs of the lens holder 32 of the first optical unit 30, and a reference numeral 45 a 3 refer to a screw fix portion 45 a 3 of the second optical unit 40.

FIG. 7 is a perspective view from a direction indicated by an arrow A in FIG. 6 and illustrates the lighting unit 20, the projection lens unit 31, and the image forming unit 10.

At an upper side of the housing-like portion 261 of the lighting bracket 26, an upper plate 26 b is disposed orthogonally to Y direction in the figure. At four corner of this upper plate 26 b, through holes for letting through screws for screwing the first optical unit 30 are disposed (in FIG. 7, through holes 26 c 1 and 26 c 2 are illustrated). Positioning holes 26 e 1 and 26 e 2 for positioning the first optical unit 30 to the lighting unit 20 are disposed adjacent to the through holes 26 c 1 and 26 c 2 located at the front side in X direction in the figure. Among two positioning holes disposed at the front side in X direction in the figure, the positioning hole 26 e 1 at a side of which the color wheel 21 is disposed is a main reference for the positioning and has a round hole shape. The positioning hole 26 e 2 at an opposite side of the color wheel 21 installation side is a sub reference for the positioning, and has an elongate hole extending in Z direction. A periphery of through hole 26 c 1 and a periphery of through hole 26 c 2 are protruded from a surface of the upper plate 26 b of the lighting bracket 26. These protruded peripheries functions as positioning protrusions 26 f for positioning the first optical unit 30 in Y direction. If the positioning accuracy in Y direction should be improved without employing the positioning protrusions 26 f, it is required to improve an entire flatness of the upper plate 26 b of the lighting bracket 26. This raises the cost. On the other hand, by employing the positioning protrusions 26 f, it is enough to improve the flatness of the positioning protrusions 26 f only. Thereby, the positioning accuracy in Y direction can be improved, while saving the cost.

A light shielding plate 262 is disposed at the opening of the upper plate 26 b of the lighting bracket 26. A lower portion of the projection lens unit 31 engages with the light shielding plate 262, so that the light from the upper side to inside of the housing-like portion 261 is shielded.

A space between the through hole 26 c 1 and the through hole 26 c 2 of the lighting bracket 26 is cut off so as not to be an obstacle when the second optical unit 40 is screwed to the first optical unit 30, which will be described later.

At the cooler wheel side (the front side in Z direction in the figure) of the lighting bracket 26, a cylinder-like light source positioning joint portion 26 a 3 is disposed. The cylinder-like light source positioning joint portion 26 a 3 has a vertical through hole into which the protrusion-like light source positioning portion 64 a 3 (see FIG. 4) formed on the upper surface of the holder 64 of the light source unit 60 fits or engages. Below the light source positioning joint portion 26 a 3, two protrusion-like light source positioning joint portions 26 a 1 and 26 a 2 are disposed, which engage with two hole-like light source positioning portion 64 a 1 and 64 a 2 formed on the light source bracket 62 side of the holder 64. By engaging three light source positioning portions 64 a 1 to 64 a 3 of the holder 64 with three light source positioning joint portions 26 a 1 to 26 a 3 formed on the lightning bracket 26 of the lighting unit 20, the light unit 60 is positioned and fixed to the lighting unit (see FIG. 3).

To the lighting bracket 26, a lighting cover 28 for covering the color wheel 21 and the light tunnel 22 is attached.

FIG. 8 is for explaining the light path L of the light in the lighting unit 20.

The color wheel 21 has a disc-like shape, and is fixed to a motor shaft of a color motor 21 a. The color wheel 21 is provided with filters such as red (R) filer, green (G) filter, and blue (B) filter in a rotating direction. The light collected by the reflector disposed on the holder 64 of the light source unit 60 reaches a peripheral portion of the color wheel 21 through the emitting window 63. The light reached the peripheral portion of the color wheel 21 is split into R, G and B in a time divided manner by the rotation of the color wheel 21.

The light split by the color wheel 21 enters the light tunnel. 22. The light tunnel 22 has a square cylinder shape. The inner peripheral surface of the light tunnel 22 is a mirror surface. The light entered the light tunnel 22 is formed into a uniform surface light source while reflected multiple times on the inner surface of the light tunnel 22, and emitted to the relay lenses 23.

The light passed through the light tunnel 22 transmits two relay lenses 23, and is reflected by the cylinder mirror 24 and the concave mirror 25, and is collected on an image forming surface of the DMD 12 where an image is formed.

Next, the image forming unit 10 will be described.

FIG. 9 perspectively illustrates the image forming unit 10.

As illustrated in FIG. 9, the image forming unit 10 is provided with a DMD board 11 to which the DMD 12 is attached. The DMD 12 is attached to a socket 11 a formed on the DMD board 11 so that the image forming surface in which micromirrors are arranged in an array (grid) faces upward. The DMD board 11 is provided with a drive circuit and the like for driving the DMD mirror. A heat sink 13 as a cooling unit to cool down the DMD 12 is fixed to a back side (an opposite side of the socket 11 a formed side) of the DMD board 1. A portion of the DMD board 11 to which the DMD 12 is attached is opened through. The heat sink 13 is provided with a protrusion portion 13 a (see FIG. 8) which engages with the through hole of the DMD board 11. A leading head of the protrusion portion 13 a is flattened. This protrusion portion 13 a is inserted into the through hole of the DMD board 11, so that the flat portion at the leading edge of the protrusion portion 13 a abuts on the back surface (the opposite surface of the image forming surface) of the DMD 12. It is possible to improve the adhesiveness and thermal conductivity between the flat portion of the protrusion portion 13 a and the back surface of the DMD 12 by applying an elastically deformable heat transfer sheet to the flat portion and/or a portion of the back surface of the DMD 12 on which the heat sink 13 abuts.

By a fix unit 14, the heat sink 13 is pressured and fixed to the DMD board 11 at a side opposite to a side which the socket 11 a is formed. The fix unit 14 includes plate-like fix portions 14 a. One of the plate-like portions 14 a faces the back surface of the DMD board 11 at a right side in the figure. The other plate-like portion 14 a faces the back surface of the DMD board 11 at a left side in the figure. Pressure portions 14 b are disposed near both ends in X direction of each fix portion 14 a so that right and left fix portions 14 a are connected.

The heat sink 13 is pressured and fixed by the fix unit 14 to the DMD board 11 at a side opposite to a side which the socket 11 a is formed, when the image forming unit 10 is screwed to the lighting bracket 26 (see FIG. 7).

Now, the fix procedure of the image forming unit 10 to the lighting bracket 26 will be described. First, the image forming unit 10 is positioned to the lighting bracket 26 so that the DMD 12 faces the opening of the lighting through hole 26 d formed at the lower surface of the lighting bracket 26 of the lighting unit 20 as illustrated in FIG. 6. Next, a screw is inserted from the lower side so that the screw goes through the through hole of the fix portion 14 a and the through hole of the DMD board 11. The screw is screwed into a screw hole formed at the lower side of the screw portion 262 (see FIG. 3) formed on the lighting bracket 26. As the screw is screwed into the screw portion 262 of the lighting bracket 26, the pressure portion 14 b presses the heat sink 13 toward the DMD board 11. Thereby, the heat sink 13 is pressed and fixed by the fix unit 14 to a surface of the DMD board 11 opposite to a surface on which the socket 11 a is formed.

Thus, the image forming unit 10 is fixed to the lighting unit 26. As illustrated in FIG. 6, three legs 29 also support the weight of the image forming unit 10.

In the image forming surface of the DMD 12, a plurality of movable micromirrors are arranged in an array (grid). Each of micromirrors can tilt its mirror surface by a predetermined angle around a torsion axis. Thus, each of micromirrors can take ON position or OFF position. If a micromirror is at ON position, the light from the light source 61 is reflected to the first optical system 70 (see FIG. 2), as illustrated by an arrow L2 in FIG. 8. If a micromirror is at OFF position, the light from the light source 61 is reflected to the OFF light plate 27 (see an arrow L1 in FIG. 8) held at the lateral side of the lighting bracket 26 as illustrated in FIG. 7. Therefore, by driving each mirror independently, it is possible to control the light projection for each pixel of the image data and thus form the image.

The light reflected to the OFF light plate 27 is absorbed as heat and then cooled by an ambient air flow.

Next, the first optical unit 30 will be described.

FIG. 10 perspectively illustrates the first optical unit 30 with the lighting unit 20 and the image forming unit 10.

As illustrated in FIG. 10, the first optical unit 30 is disposed above the lighting unit 20. The first optical unit 30 is provided with the projection lens unit 31 holding the first optical system 70 (see FIG. 2) including a plurality of lenses, and the lens holder 32 for holding this projection lens unit 31.

The lens holder 32 has four legs 32 a 1 to 32 a 4 extending downward (in FIG. 10, only legs 32 a 2 and 32 a 3 are illustrated. The leg 32 a 1 is illustrated in FIG. 3, and the leg 32 a 4 is illustrated in FIG. 6). A screw hole is formed at a bottom surface of each of legs 32 a 1 to 32 a 4, for screwing each leg is screwed to the lighting bracket 26.

The projection lens unit 31 is provided with a focus gear 36 with which an idle gear 35 engages. The idle gear 35 engages with a lever gear 34. A focus lever 33 is fixed to a rotational axis of the lever gear 34. The leading edge of the focus lever 33 is exposed from the main body as illustrated in FIG. 1.

When the focus lever 33 is moved, the focus gear 36 is rotated via the lever gear 34 and the idle gear 35. When the focus gear 36 is rotated, the plurality of lenses composing the first optical system 70 in the projection lens unit 31 is moved to predetermined directions so that a focus of the projection image is adjusted.

The lens holder 32 has four screw through holes 32 c 1 to 32 c 4 through which screws 48 penetrate for screwing the second optical unit 40 to the first optical unit 30 (in FIG. 10, three screw through holes 32 c 1 to 32 c 3 are illustrated. Each of three screw through holes is illustrated in a state that a screw 48 is penetrated. The edge of the screw 48 is viewed in the figure.) Around each of screw through holes 32 c 1 to 32 c 4, the second optical unit positioning protrusions 32 d 1 to 32 d 4 protruded from the surface of the lens holder 32 are formed (in FIGS. 10, 32 d 1 to 32 d 3 are illustrated).

FIG. 11 is a sectional view along A-A line in FIG. 10.

As illustrated in FIG. 11, legs 32 a 1 and 32 a 2 are provided with positioning joint protrusions 32 b 1 and 32 b 2, respectively. The positioning joint protrusion 32 b 1 at the right side in the figure is inserted into the round hole shaped positioning hole 26 e 1 which is formed as the main reference at the upper plate 26 b of the lighting bracket 26. The positioning joint protrusion 32 b 2 at the left side in the figure is inserted into the elongate hole shaped positioning hole 26 e 2 which is formed as the sub reference on the upper plate 26 b of the lighting bracket 26. Thus, the positioning in Z direction and X direction is done. Screws 37 are inserted into through holes 26 c 1 to 26 c 4 formed at the upper plate 26 b of the lighting bracket 26, so that screws 37 are screwed into screw holes formed on each of legs 32 a 1 to 32 a 4 of the lens holder 32, and the first optical unit 70 is positioned and fixed to the lighting unit 20.

The upper portion of the projection lens unit 31 above the lens holder 32 is covered by a mirror holder 45 (see FIG. 13) of the second optical unit, which will be described later. As illustrated in FIG. 3, below the lens holder 32 of the projection lens unit 31, a portion of the projection lens unit 31 between the lens holder 32 and the upper plate 26 b of the lighting bracket 26 of the lighting unit 20 is exposed. However, the light cannot enter from this exposed portion to the light path of the image, since the projection lens unit 31 engages with the lens holder 32.

Next, the second optical unit 40 will be described.

FIG. 12 perspectively illustrates the second optical system included in the second optical unit 49, while also illustrating the projection lens unit 31, the lighting unit 20 and the image forming unit 10.

As illustrated in FIG. 12, the second optical unit 40 is provided with the reflecting mirror 41 composing the second optical system, and the concavely curved mirror 42. A reflecting surface of the curved mirror 42 may be a spherical surface, a rotationally symmetric aspheric surface, a free curved surface or the like.

FIG. 13 perspectively illustrates the second optical unit 40 with the first optical unit 30, the lighting unit 20, and the image forming unit 10.

As illustrated in FIG. 13, the second optical unit 40 is provided with a transmissive glass 51 for transmitting the light image reflected from the curved mirror 42 and for protecting optical components in the unit from dust.

The second optical unit 40 includes a mirror bracket 43 for holding the reflecting mirror 41 and the transmissive glass 51, a free mirror bracket 44 for holding the curved mirror 42, and the mirror holder 45 to which the mirror bracket 43 and the free mirror bracket 44 are attached.

The mirror holder 45 has a box shape. Specifically, it has a U shape when viewed from the upper side in which the upper side, the bottom side, and the depth side of X direction in the figure of the box are opened. Edge portions of the upper opening of the mirror holder 45 extend from the front side to the depth side in X direction at the front side and the depth side in Z direction. Each of these edge portions has an inclined portion and a parallel portion. The inclined portion inclines so that it is raised as it goes to the depth in X direction in the figure. The parallel portion is parallel to X direction in the figure. The inclined portion is on the front side of the parallel portion in X direction. An edge portion of the upper opening of the mirror holder 45 extending in Z direction at the front side in X direction in the figure is parallel to Z direction in the figure.

The mirror bracket 43 is attached to the upper part of the mirror holder 45. The mirror bracket 43 has an inclined surface 43 a and a parallel surface 43 b. The inclined surface 43 a abuts on the inclined portion of the upper opening edges of the mirror holder 35, and inclines so that it is raised as it goes to the depth in X direction in the figure. The parallel surface 43 b, which is parallel to X direction, abuts on the parallel portion of the upper opening edges of the mirror holder 45. The inclined surface 43 a and the parallel surface 43 b have openings, respectively. In these openings, the reflecting mirror 41 is held so that the opening of the inclined surface 43 a is closed, and the transmissive glass 51 is held so that the opening of the parallel surface 43 b is closed.

The reflecting mirror 41 is positioned and fixed to the inclined surface 43 a of the mirror bracket 43 by pressing Z direction both ends of the reflecting mirror 41 against the inclined surface 43 a of the mirror bracket 43 by a flat spring-like mirror pressing members 46. One Z direction end of the reflecting mirror 41 is fixed by two mirror pressing members 46, and the other Z direction end of the reflecting mirror 41 is fixed by one mirror pressing member 46.

The transmissive glass 51 is positioned and fixed to the mirror bracket 43 by pressing Z direction both ends of the transmissive glass 51 against the parallel surface 43 b of the mirror bracket 43 by a flat spring-like glass pressing members 47. Each Z direction end of the transmissive glass 51 is fixed by one glass pressing member 47, respectively.

The free mirror bracket 44 for holding the curved mirror 42 has arms 44 a at Z direction both sides thereof. Each of arms 44 a declines so that it is lowered as it goes to the front side from the depth side in X direction in the figure. The free mirror bracket 44 also has a connecting portion 44 b for connecting two arms 44 a at an upper side of two arms 44 a. With regard to this free mirror bracket 44, arms 44 a are attached to the mirror holder 45 so that the curved mirror 42 covers the X direction depth side opening of the mirror holder 45.

The curved mirror 42 is fixed in such a manner that a substantial central portion of the transmissive glass side end of the curved mirror 42 is pressed against the connecting portion 44 b of the free mirror bracket 44 by a plate spring-like free mirror pressing member 49, and Z direction both ends of the curved mirror 42 on the first optical system side are fixed to arms 44 a of the free mirror bracket 44 by screws.

The second optical unit 40 is stacked on and fixed to the lens holder 32 of the first optical unit 30. Specifically, an under surface 451 is formed under the mirror holder 45 which faces the upper surface of the lens holder 32. The under surface 451 has four cylindrical screw joints 45 a 1 to 45 a 4 (only 45 a 1 and 45 a 2 are illustrated in FIGS. 13, and 45 a 3 is illustrated in FIG. 6) formed for screwing the second optical unit 40 to the first optical unit 30. The second optical unit 40 is fixed to the first optical unit 30 in such a manner that screws 48 are penetrated through screw holes 32 c 1 to 32 c 4 formed on the lens holder 32 of the first optical unit 30, and then screwed and fastened into screw joints 45 a 1 to 45 a 4. At this time, the under surface of the mirror holder 45 of the second optical unit 40 abuts on the second optical unit positioning protrusions 32 d 1 to 32 d 4 of the lens holder 32, so that the second optical unit 40 is positioned in Y direction and fixed.

When the second optical unit 40 is stacked on and fixed to the lens holder 32 of the first optical unit 30, the upper portion of the projection lens unit 31 above the lens holder 32 as illustrated in FIG. 10 is housed in the mirror holder 45 of the second optical unit 40. When the second optical unit 40 is stacked on and fixed to the lens holder 32 of the first optical unit 30, a gap is made between the curved mirror 42 and the lens holder 32. The idle gear 35 (see FIG. 10) is inserted into the gap.

FIG. 14 perspectively illustrates the light paths from the first optical system 70 to the projection plane 101 (screen).

The light beam passed through the projection lens unit 31 composing the first optical system 70 forms an intermediate image conjugate to the image formed on the DMD 12 between the reflecting mirror 41 and the curved mirror 42. This intermediate image is formed as a curved mirror image between the reflecting mirror 41 and the curved mirror 42. Next, the diverging light after forming the intermediate image enters the concavely curved mirror 42 to become a convergent light. By this convergent light through the curved mirror 42, the intermediate image becomes a “further enlarged image” to be projected and formed on the projection plane 101.

Thus, owing to the structure in which the projection optical system is composed of the first optical system 70 and the second optical system, the intermediate image is formed between the first optical system 70 and the curved mirror 42 of the second optical system, and the intermediate image is enlarged and projected by the curved mirror 42, the projection distance can be shortened. Thus, the projectors can be used in small rooms.

As illustrated in FIG. 14, the first optical unit 30 and the second optical unit 40 are stacked on and fixed to the lighting bracket 26. Furthermore, the image forming unit 10 is also fixed. Therefore, legs 29 of the lighting bracket 26 are fixed to the base component 53 so that the legs 29 support weights of the first optical unit 30, the second optical unit 40 and the image forming unit 10.

FIG. 15 schematically illustrates an arrangement of units in the projector.

As illustrated in FIG. 15, the image forming unit 10, the lighting unit 20, the first optical unit 30 and the second optical unit 40 are arranged in a stacked manner in Y direction which is a short axis direction of the projection plane. Relative to stacked units of the image forming unit 10, the lighting unit 20, the first optical unit 30 and the second optical unit 40, the light source unit 60 is disposed in Z direction which is a long axis direction of the projection plane. Thus, in the present embodiment, the image forming unit 10, the lighting unit 20, the first optical unit 30, the second optical unit 40 and the light source unit 60 are arranged in Y direction or Z direction which are parallel to the projection plane 101. More specifically, the image forming unit 10 and the lighting unit 20 form the image forming part A, while the first optical unit 30 and the second optical unit 40 form the projection optical part B. The image forming part A, the projection optical part B, and the light source unit 60 are arranged so that a light emitting surface of the light source unit 60 intersects a surface of the stacked body of the image forming part A and the projection optical system B which is parallel to the projection image and the projection plane 101. The image forming part A and the light source unit 60 are arranged along the same line parallel to the base component 53. The image forming part A and the projection optical part B are arranged along the same line perpendicular to the base component 53, in the order of the image forming part A and the projection optical part B from the base component 53.

In the present embodiment, above the light source unit 60, a power source unit 80 is stacked for supplying an electrical power to the light source 61 and the DMD 12. The light source unit 60, the power source unit 80, the image forming part A and the projection optical part B are housed in a case of the projector 1 made of an outer cover (see FIG. 20), which will be described later, covering the upper surface of the projector, the base component 53 and the surrounding of the projector 1.

FIG. 16 illustrates an example of usage of the projector 1 according to the present embodiment. FIG. 17 illustrates an example of usage of a conventional projector 1A. FIG. 18 illustrates an example of usage of a projector 1B in which a light source 61 and a lighting unit 20 are arranged in a direction orthogonal to a projection plane 101.

As illustrated in FIG. 16 to FIG. 18, the projector 1 is used in such a manner that the projector 1 is put on a table 100 and an image is projected on the projection plane 101 such as a white board, when used in a meeting room or the like for example.

As illustrated in FIG. 17, in the conventional projector 1A, a DMD 12 (image forming element), a lighting unit 20, a first optical system 70, and a second optical system (concave mirror 42) are arranged in series in a direction orthogonal to a plane of a projection image projected on a projection plane 101. Therefore, the projector 1A is elongated in the direction (X direction) orthogonal to the projection plane of the projector 1A. Thus, the projector 1A occupies a space in the direction orthogonal to the projection plane 101. Desks and chairs used by viewers of the image projected on the projection screen 101 are generally arranged in the direction orthogonal to the projection plane. Thus, if the projector occupies the space in the direction orthogonal to the projection plane, the layout space allowed for desks and chairs is limited. It is inconvenient.

In the projector 1B illustrated in FIG. 18, a DMD 12 (image forming element), a lighting unit 20 and a first optical system 70 are arranged in series parallel to a plane of a projection image projected on a projection plane 101. Therefore, in comparison with the projector 1A illustrated in FIG. 17, a length in a direction orthogonal to the projection plane 101 can be shortened. However, in the projector 1B illustrated in FIG. 18, relative to the lighting unit 20, a light source 61 is arranged in the direction orthogonal to the plane of the projection image. Therefore, the length in the direction orthogonal to the projection plane 101 of the projector cannot be sufficiently shortened.

On the other hand, in the projector 1 according to the present embodiment illustrated in FIG. 16, the image forming part A composed of the image forming unit 10 and the lighting unit 20 and the projection optical part B composed of the first optical unit 30 and the reflecting mirror 41 are arranged in series along Y direction in the figure among directions parallel to the projection plane 101 and the image plane of the projection image projected on the projection plane 101. Furthermore, the light source unit 60 and the lighting unit 20 are arranged in series along Z direction in the figure among directions parallel to the plane of the projection image projected on the projection plane 101. Namely, the projector 1 according to the present embodiment has a configuration in which the light source unit 60, the image forming unit 10, the lighting unit 20, the first optical unit 30, and the reflecting mirror 41 are arranged in directions (Z and Y directions in the figure) parallel to the plane of the projection image projected on the projection plane 101. Each of the light source unit 60, the image forming unit 10, the lighting unit 20, the first optical unit 30, and the reflecting mirror 41 is arranged parallel to the projection plane and the image plane of the projection image. Thus, since the light source unit 60, the image forming unit 10, the lighting unit 20, the first optical unit 30, and the reflecting mirror 41 are arranged in directions (Z and Y directions in the figure) parallel to the plane of the projection image projected on the projection plane 101, a length in a direction (X direction in the figure) orthogonal to the projection plane 101 can be shortened as illustrated in FIG. 16, in comparison with projectors illustrated in FIG. 17 and FIG. 18. Thereby, the projector 1 cannot be an obstacle for the layout of desks and chairs in view of spaces. Thus, it is possible to provide the convenient projector 1.

In the present embodiment, as illustrated in FIG. 15, above the light source unit 60, the power source unit 80 for supplying the electric power to the light source 61 and the DMD 12 are disposed in a stacked manner. Thereby, a length of the projected 1 in Z direction is shortened.

FIG. 19 illustrates another example of usage of the projector 1 according to the present embodiment.

As illustrated in FIG. 19, the projector 1 according to the present embodiment can be used by hanging from a ceiling 105. Also in this case, the length of the projector 1 in the direction orthogonal to the projection plane 101 is short. Therefore, when the projector 1 is installed at the ceiling 105, the projector 1 can be installed without affecting a lighting equipment 106 disposed on the ceiling 105.

In the present embodiment, the second optical system is composed of the reflecting mirror 41 and the curved mirror 42. However, the second optical system may be composed only of the curved mirror 42. The reflecting mirror may be a flat mirror, a mirror having a positive refractive power, or a mirror having a negative refractive power. In the present embodiment, the concave mirror is used as the curved mirror 42. However, a convex mirror may be used. In this case, the first optical system 70 is configured so that an intermediate image is not formed between the first optical system 70 and the curved mirror 42.

The light source 61 is to be replaced periodically, since its life time ends after use over time. For this purpose, in the present embodiment, the light source unit 60 is arranged detachably from and attachably to the main body.

FIG. 20 perspectively illustrates an installation side of the projector 1.

As illustrated in FIG. 20, the base component 53 constituting the bottom surface of the projector 1 is provided with an access cover 54 (openable/closeable cover). The access cover 54 is provided with a rotating operating member 54 a. The rotating operating member 54 a can be rotated to release the lock between the access cover 54 and the main body, so that the access cover can be removed from the main body. Electrical power air inlets 56 are disposed adjacent in X direction to the access cover 54 of the base component 53.

As illustrated in FIG. 20, in one of XY planes of an outer cover 59 of the projector 1, an air inlet 84, and an external input portion 88 from which the image data or the like is input from an external device such as a PC are disposed.

FIG. 21 perspectively illustrates a state that the access cover 54 is removed from the main body.

As illustrated in FIG. 21, if the access cover 54 is removed, a side of the light source bracket 62 opposite to a side on which the light source 61 is mounted in the light source unit 60 is exposed. The airflow path 65 formed so as to cubically protrude toward the access cover 54 is used as the handle portion 68 allowing for the user to pinch it by fingers for the replacement of the light source unit 60.

When the light source unit 60 is to be removed from the main body, the handle portion 68 or a finger grip 66 is pinched and pulled toward the nearer side in the figure, so that the light source unit 60 is removed from the opening of the main body. When the light source unit 60 is to be mounted to the main body, the light source unit 60 is inserted from the opening of the main body. As the light source unit 60 is inserted into the main body, the connecting portion 62 a as illustrated in FIG. 4 connects with the power source side connector of the main body. Three light source positioning portions 64 a 1 to 64 a 3 of the holder 64 as illustrated in FIG. 4 engage with three light source positioning joint portions 26 a 1 to 26 a 3 formed on the lighting bracket 26 of the lighting unit 20 as illustrated in FIG. 7, so that the light source unit 60 is positioned to the main body. Thus, the mounting of the light source unit 60 is completed. Then, the access cover 54 is attached to the base component 53.

The base component 53 has three legs 55. By rotating these legs 55, the protruded extent of legs 55 from the base component 53 can be changed, and the adjustment in the height direction (Y direction) can be done.

As illustrated in FIG. 21, in the other XY plane of the outer cover 59, an exhaust outlet 85 is disposed.

FIG. 22 is a view illustrating air flows in the projector 1 according to the present embodiment. In FIG. 22, the projector 1 is viewed from the direction (X direction) orthogonal to the projection plane 101. In FIG. 23, schematically illustrated components in FIG. 22 are specifically illustrated carrying the same reference numerals. In FIG. 22 and FIG. 23, arrows indicate directions to which air flows. FIG. 24 is a cross section along A-A line of FIG. 23. FIG. 25 is a cross section along B-B line of FIG. 23.

As illustrated in FIG. 22, at one side (left side in the figure) of the projector 1, the air inlet 84 is formed for taking an ambient air into the projector 1. At another side (right side in the figure) of the projector 1, the exhaust outlet 85 is formed for discharging the air inside of the projector 1. An exhaust fan 86 is disposed so as to face the exhaust outlet 86.

The exhaust outlet 85 and a part of the air inlet 84 are located at a level between the light source unit 60 and the operating part 83, when the projector 1 is viewed from the direction (X direction) orthogonal to the projection plane 101. Thereby, the ambient air taken from the air inlet 84 flows to ZY plane of the mirror holder 45 and the back side of the curved mirror 42 of the second optical unit 40 as illustrated in FIG. 12. Along the mirror holder 45 and the back side of the curved mirror 42, the air flows toward the exhaust outlet 85. The power source unit 80 disposed above the light source unit 60 has an arch-like shape when viewed from Z direction in the figure. The air moved along the mirror holder 45 and the back side of the curved mirror 42 toward the exhaust outlet 84 flows into a space surrounded by the power source unit 80 and is then discharged from the exhaust outlet 85.

Thus, the exhaust outlet and the part of the air inlet are located at a level between the light source unit 60 and the operating part 83 when the projector 1 is viewed from the direction (X direction) orthogonal to the projection plane 101. Thereby, there is generated the airflow which flows between the light source unit 60 and the operating part 83 and is then discharged from the exhaust outlet 85.

A light source blower 95 is disposed at a position allowing for suctioning the air around the color motor 21 a (see FIG. 6) to drive and rotate the color wheel 21 of the lighting unit 20. Thereby, the color motor 21 a can be cooled by the airflow generated by the air suction of the light source blower 95.

The air suctioned by the light source blower 95 flows to the light source air inlet 64 b (see FIG. 4) of the holder 64 through the light source duct 96. A part of the air flows into the light source duct 96 flows from an opening 96 a, which is formed on the light source duct 96 on a side facing the outer cover 59 (see FIG. 20), to between the light source housing 97 and the outer cover 59.

The air flowing from the opening 96 a of the light source duct 96 to between the light source housing 97 and the outer cover 59 cools down the light source housing 97 and the outer cover 59, and is then discharged from the exhaust outlet 85 by the exhaust fan 86.

The air flowing to the light source air inlet 64 b flows into the light source 61. After cooling the light source 61, the air is discharged from the light source air outlet 64 c formed on the upper surface of the holder 64. The air discharged from the light source air outlet 64 c flows into the space surrounded by the power source unit 80 from the opening on the upper surface of the light source housing 97. Then, the air is mixed with the low temperature air which flows along the outside of the second optical unit 40 and flows into the space surrounded by the power source unit 80. Then, the air is discharged from the exhaust outlet 85 by the exhaust fan 86. Thus, the high temperature air discharged from the light source air outlet 64 c is mixed with the ambient air and then discharged to the ambient. Thereby, it is possible to prevent the temperature rise of the air discharged from the exhaust outlet 85.

The operating part 83 operated by the user is preferably formed on the upper surface of the apparatus for the easy operation by the user. In the present embodiment, however, since the transmissive glass 51 is disposed on the upper surface of the projector 1 for the purpose of projecting the image on the projection plane 101, the operating part 83 needs to be disposed above the light source 61 as if they overlap each other when the projector 1 is viewed from the Y direction.

In the present embodiment, the high temperature air after cooling the light source 61 is guided to the exhaust outlet 85 by the airflow from the air inlet 84 to the exhaust outlet 85 between the light source unit 60 and the operating part 83. This high temperature air is prevented from flowing to the operating part 83. Thereby, the operating part 83 is prevented from being heated by the high temperature air after cooling the light source 61. Furthermore, a part of the air which flows from the air inlet 84 to the exhaust outlet 85 through the outside of the second optical unit 40 cools the operating part 83 by flowing beneath the operating part 83. This also contributes to the prevention of the temperature raise of the operating part 83.

Owing to the air suction of the exhaust fan 86, the ambient air is suctioned from the power source air inlets 56 formed on the base component 53 as illustrated in FIG. 20. At the X direction depth side in the figure beyond the light source housing 97, a ballast board 3 a (see FIG. 24 and FIG. 25) for supplying a stable electric power (electric current) to the light source 61 is disposed. The ambient air suctioned from the power source air inlets 56 moves upward through between the light source housing 97 and the ballast board. While this movement, the air cools the ballast board. Then, the air flows into the space surrounded by the power source unit 80 disposed above the ballast board. Then, the air is discharged from the exhaust outlet 85 by the exhaust fan 86.

At the lower left side of the main body in the figure, a cooling unit 120 is disposed for cooling the heat sink 13 of the image forming unit 10 and the light source bracket 62 of the light source unit 60. The cooling unit 120 is provided with an air intake blower 91, a vertical duct 92, and a horizontal duct 93.

Referring to FIG. 27 also, airflow from the air intake blower 91 will be explained. The air intake blower 91 is disposed facing the air inlet 84 at the lower part of the inlet 84. The ambient air is taken from one side of the blower 91 facing the air inlet 84 through the air inlet 84. The air inside of the apparatus is taken from the other side of the blower 91 which is opposite to the one side facing the air inlet 84. The taken air is directed to the vertical duct 92 disposed under the blower 91. The air directed to the vertical duct 92 moves downward and is then directed to the horizontal duct 93 connected to the vertical duct 92 at the lower part of the duct 92.

In the horizontal duct 93, there is a heat sink 13 attached to the back side of the image forming surface of the DMD 12. The heat sink 13 is cooled by the air flowing in the horizontal duct 93. By cooling the heat sink 13, the DMD 12 can be cooled effectively. Thus, the DMD 12 can be prevented from being heated to high temperature.

The air moved through the horizontal duct 93 flows in the airflow path 65 or the openings 65 a formed in the light source bracket 62 of the light source unit 60 as illustrated in FIG. 4. The air entered the openings 65 a flows to between the access cover 54 and the light source bracket 62, so that the access cover 54 is cooled.

On the other hand, the air entered the airflow path 65 cools the light source bracket 62 and then flows to a part of the light source 61 opposite to the emitting side of the light source 61, so that a part of the light source 61 opposite to the reflecting surface of the reflector 67 is cooled. Therefore, the air flowing through the air flow path 65 takes heat from both the light source bracket 62 and the light source 61. The air passed around the reflector 67 flows through an exhaust duct 94 which directs the air from a level (height) of the light source bracket 62 to a level around the lower portion of the exhaust fan 86. Then, the air combines with the air discharged from the light source air outlet 64 c, and flows to the exhaust outlet 85 through a fluid guide 87. The air is discharged from the exhaust outlet 85 by the exhaust fan 86. On the other hand, the air which flows between the access cover 54 and the light source bracket 62 through the openings 65 a moves inside of the apparatus after cooling the access cover 54, so that the air is discharged from the exhaust outlet 85 by the exhaust fan 86.

FIG. 26 perspectively illustrates the cooling unit 120 with the lighting unit 20 and the light source unit 60. The layout of the cooling unit, the lighting unit 20, and the light source unit 60 is illustrated in FIG. 26.

As understood from FIG. 26, a space allowing for the installation of the horizontal duct 93 under the lighting unit 20 is ensured by legs 29 which support weights of the image forming unit 10, the lighting unit 20, the first optical unit 30, and the second optical unit 40.

FIG. 27 is a longitudinal section view of FIG. 26. An arrow indicates airflow from the air intake blower 91 to the vicinity of the reflector 67 through the airflow path 65. The air flowing from the air intake blower 91 flows as indicated by arrows K0, K1, and K3. The light source unit 60 is attached to the projector 1 so that the light source bracket 62 and the airflow path 65 face the base component 53. Thereby, a flow path for cooling the reflector 67 of the light source 61 and the horizontal duct 93 as a flow path for cooling the heat sink 13 are also disposed on the base component 53. Consequently, a width of the projector 1 in a direction orthogonal to the projection plane can be shortened.

FIG. 28 perspectively illustrates the horizontal duct 93 and the light source bracket 62 on the base component 53.

As illustrated in FIG. 28, the horizontal duct 93 is fixed to the base component 53 of the projector 1. The horizontal duct 93 has an opening at a part of the upper surface thereof. The image forming unit 10 is mounted on the horizontal duct 93, so that the heat sink 13 of the image forming unit 10 is inserted in this opening.

FIG. 29 illustrates airflow from the horizontal duct 93 to the light source bracket 62 when viewed from the under side of the base component 53. FIG. 30 illustrates airflow from the horizontal duct 93 to the light source bracket 62 when viewed from the upper side of the base component 53.

As illustrated in FIG. 29 and FIG. 30, the air from the horizontal duct 93 flows into the airflow path 65 or openings 65 a formed in the light source bracket 62 of the light source unit 60. The air entered the openings 65 a flows to between the access cover 54 and the light source bracket 62, so that the access cover 54 is cooled. Therefore, it is possible to take heat from the access cover 54. With regard to the airflow path 65 itself, heat is taken from both the light source 61 side thereof and the access cover 54 side thereof.

In the present embodiment, a halogen lamp, a metal halide lamp, a high pressure mercury lamp or the like may be used as the light source 61. Thereby, the light source 61 becomes high temperature when emitting light. The light source bracket 62 and the access cover 54 become also high temperature due to heat conductance and heat radiation from the light source 61. When the light source unit 60 is replaced at the end of the lifetime, the access cover 54 and the light source bracket 62 are grabbed or pinched by the user. Therefore, unless the access cover 54 and the light source bracket 62 are cooled, the light source unit 60 cannot be replaced. It is inconvenient. In the present embodiment, however, the airflow path 65 is disposed in the light source bracket 62 as an airflow path formed in the handle portion 68 having an outer shape allowing for the user to pinch it when removing the light source unit 60, in order to cool the light source bracket 62 by passing the air through the path 65, and to cool the access cover 54 by passing the air between the access cover 54 and the light source bracket 62, as mentioned above. Thereby, the access cover 54 and the light source bracket 62 can be prevented form being heated to high temperature. Thereby, after the apparatus is stopped, the access cover 54 and the light source bracket 62 can be quickly cooled down to a temperature at which the user can grab or pinch the cover 54 or the bracket 62. Therefore, in a case that the light source unit 60 needs to be replaced when the lifetime of the light source 61 ends during the operation of the apparatus, the user can grab or pinch the access cover 54 and/or the handle portion (airflow path 65) of the light source unit 60 at early stage. Therefore, the light source unit 60 can be replaced with a new one at an earlier stage than the replacement in the conventional projectors. Consequently, the downtime of the apparatus can be shortened.

As mentioned above, the airflow path 65 is a part into which the air flows and which is cooled intensively. Thus, the airflow path 65 is a part the temperature of which is suppressed to low level in the light source bracket 62. Therefore, owing to the configuration in which the airflow path 65 can be used as the handle portion, the light source unit 60 can be replaced with a new one at an earlier stage. Consequently, the downtime of the apparatus can be further shortened.

In the present embodiment, as mentioned above, the light source bracket 62 is provided with the airflow path 65, so that the light source bracket 62 is cooled and thereby the temperature rise of the light source 61 is suppressed. Thereby, even if the amount of the air which flows into the light source 61 is decreased in comparison with the conventional amount, the light source 61 can be cooled well. Thereby, it is possible to reduce the rotation speed (rpm) of the light source blower 95. Thus, a wind noise (kazekirion) of the light source blower 95 can be reduced. Thereby, the noise of the apparatus can be reduced. Furthermore, since the rotation speed (rpm) of the light source blower 95 can be reduced, the electrical power for the apparatus can be saved. Furthermore, it is possible to use a small light source blower 95 generating a small amount of airflow. Thus, the apparatus can be downsized.

The above explanations are only examples. The present invention has specific effects for each of the following aspects (1) to (5) including embodiments.

(1)

An image projection apparatus includes a light source 61, a holding member 62 configured to hold the light source, and a blower. An image is formed by using light from the light source. A projection image of the formed image is formed by the apparatus. The holding member 62 includes a handle portion 68, and the handle portion 68 includes a first flow path 65 for flowing air sent from the blower.

According to the configuration as such, as mentioned in embodiments, the temperature rise of the handle portion 68 due to heat conductance and heat radiation from the light source 61 can be suppressed. Therefore, it is possible to reduce a time period from when the light source 61 is stopped until when the temperature of the handle portion 68 is so lowered that the user can grab or pinch it. Thereby, it is possible to remove the light source unit 60 from the light source unit replacement opening 53 c of the main body, at an earlier stage from when the light source 61 stops due to its end of lifetime. Consequently, the downtime of the apparatus can be shortened, since the light source unit 60 can be replaced at an earlier stage from when the light source 61 stops due to its end of lifetime.

(2)

In the image projection apparatus described in (1), air after cooling the handle portion 68 flows to the light source 61.

According to the configuration as such, as mentioned in embodiments, the temperature rise of the light source 61 can be suppressed. Thereby, it is possible to reduce an amount of air from the light source blower 95 as a blower to flow the air to the light source 61. Thus, the rotation speed of the light source blower 95 can be reduced. Thereby, the wind noise of the light source blower 95 can be reduced. Thus, the noise of the apparatus can be reduced. Furthermore, the electric energy consumption of the light source blower 95 can be reduced. Thus, the energy saving apparatus can be provided. Furthermore, it is possible to use a small blower or fan generating a small amount of air. Thus, the apparatus can be downsized.

(3)

In the image projection apparatus described in (1) or (2), a main body of the apparatus includes an opening for attaching or detaching the light source to or from the main body. The opening such as the light source replacement opening 53 c is formed at a position of the main body such as a base component 53 facing an installation surface on which the main body is placed.

According to the configuration as such, as mentioned in embodiments, a flow path for cooling the reflector and the horizontal duct 93 as a flow path for cooling the heat sink 13 are also formed on the base component 53. Therefore, it is possible to reduce a width in a direction orthogonal to the projection plane of the projector 1. Furthermore, the heated air of the air flowing in the airflow path 65 moves upward, while the lower temperature air moved downward. Consequently, air layers may be generated in the airflow path. By forming the opening at the installation surface of the apparatus, a side (handle portion 68) of the airflow path 65 exposed from the opening is cooled by the lower temperature air. Thus, the temperature rise of the side (handle portion 68) of the airflow path 65 exposed from the opening can be suppressed. When the light source unit 60 is to be removed, the side (handle portion 68) of the airflow path 65 exposed from the opening is grabbed or pinched. Therefore, by suppressing the temperature rise of the side (handle portion 68) of the airflow path 65 exposed from the opening, it is possible to grab or pinch the airflow path 65 and remove the light source unit from the light source replacement opening 53 c of the main body, at an earlier stage from when the light source stops. Furthermore, disposing the airflow path 65 at the installation side of the apparatus means that an airflow path for guiding the cooled air to the light source is disposed at the installation side. Therefore, it is possible to reduce an area required for installing the apparatus.

(4)

In the image projection apparatus described in any of (1) to (3), the apparatus further includes an openable and closable cover such as an access cover 54 for opening or closing the opening formed for attaching or detaching the light source 61 to or from the main body. Furthermore, the holding member 62 includes an openable and closable cover cooling flow path such as an opening 65 a for flowing air between the openable/closable cover 54 and the light source 61.

According to the configuration as such, as mentioned in embodiments, the temperature rise of the openable/closable cover 54 can be suppressed. Thus, it is possible to reduce a time period from when the light source 61 stops until when the temperature of the openable/closable cover 54 is so lowered that the user can grab or pinch it, compared with a conventional time period. Thereby, it is possible to remove the light source unit 60 from the light source replacement opening 53 c of the main body, at an earlier stage from when the light source 61 stops due to its end of lifetime. Consequently, the downtime of the apparatus can be reduced, since the light source unit 60 can be replaced at an earlier stage from when the light source 61 stops due to its end of lifetime.

According to the present invention, the handle portion includes the first flow path for flowing air. The air flows into the first flow path, so that the temperature rise of the handle portion due to heat conductance and heat radiation from the light source can be suppressed. Thereby, it is possible to lower the temperature of the handle portion to an extent of temperature allowing for the user to grab or pinch it, at an earlier stage from when the light source stops, compared to the conventional technology. Therefore, it is possible to work on the operation including grabbing or pinching the handle portion and removing the light source unit from the light source replacement opening of the main body, at an earlier stage from when the light source stops due to its end of lifetime, compared to the conventional technology. Consequently, the downtime of the apparatus can be reduced, since the light source unit can be replaced at an earlier stage from when the light source unit stops due to its end of lifetime, compared to the conventional technology.

Although the invention has been described with respect to specific embodiments for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth. 

What is claimed is:
 1. An image projection apparatus comprising: a light source, light from which is used to project an image; and a holding member configured to hold the light source, wherein the holding member includes a handle portion, the handle portion includes a first flow path for flowing air.
 2. The image projection apparatus according to claim 1, wherein a main body of the apparatus includes an opening for attaching or detaching the light source to or from the main body, and the handle portion is disposed at a position facing the opening.
 3. The image projection apparatus according to claim 2, wherein the opening is formed at a position of the main body facing an installation surface on which the main body is placed.
 4. The image projection apparatus according to claim 2, further comprising: an openable and closable cover for opening or closing the opening; and a second flow path for flowing air between the openable and closable cover and the holding member.
 5. The image projection apparatus according to claim 4, wherein a part of a wall of the first flow path is also a wall of the second flow path.
 6. A light source unit attachable to and detachable from a main body of an image projection apparatus, the light source unit comprising: a light source, light from which is used to project an image; and a holding member configured to hold the light source, wherein the holding member includes a handle portion, the handle portion includes a first flow path for flowing air. 